Electric pump for environmentally hazardous material

Abstract

An electric pump includes an impeller, a shaft and a motor having at least one permanent magnet rotor and a stator. The impeller is coupled by the shaft to the at least one permanent magnet rotor of the electric motor. A hermetically sealed housing is provided in which the shaft is supported and which has openings for delivery side and suction side connections for material to be pumped. The rotor is disposed inside the housing and the stator of the electric motor is disposed outside the housing. At least one stator carrier is attached to the housing, the stator being mounted in the at least one stator carrier. The at least one stator carrier is of one-piece configuration so as to enclose the housing across an entire circumference thereof in a cup-shaped manner. The at least one stator carrier holds a liquid for cooling the at least one stator.

We claim: 
     
       1. An electric pump comprising: an impeller, a shaft and a motor having at least one permanent magnet rotor and a stator, wherein the impeller is coupled by the shaft to the at least one permanent magnet rotor of the electric motor;   a hermetically sealed housing in which the shaft is supported and which has openings for delivery side and suction side connections for material to be pumped, wherein the housing has a thickness in a radial direction at a portion thereof between the rotor and the stator which is less than 10 mm;   wherein the rotor is disposed inside the housing and comprises circumferentially distributed, permanent magnet poles of alternating polarity which are radially spaced from the shaft;   wherein the stator of the electric motor is disposed outside the housing, is in the form of a ferromagnetic ring axially aligned with the rotor, has coil windings, and is supported outside of the housing; and   further comprising at least one stator carrier attached to the housing, the stator being mounted in the at least one stator carrier, the at least one stator carrier being of one-piece configuration so as to enclose the housing across an entire circumference thereof in a cup-shaped manner, the at least one stator carrier having a liquid for cooling the at least one stator.   
     
     
       2. A pump according to claim 1, wherein a plurality of rotors is disposed on the shaft axially beside each other, and each rotor has a stator associated therewith. 
     
     
       3. A pump according to claim 2, wherein the motor comprises a plurality of rotors and associated stator parts arranged on the shaft on one side with respect to the impeller. 
     
     
       4. A pump according to claim 2, wherein the motor comprises a plurality of rotors and associated stator parts arranged on the shaft symmetrically on both sides of the impeller. 
     
     
       5. A pump according to claim 1, wherein the housing is made of ceramics or non-ferromagnetic steel of low electrical conductivity. 
     
     
       6. A pump according to claim 5, wherein the housing comprises two parts, a first part disposed near the impeller comprised of cast steel or cast iron, and a second part disposed near the rotor comprised of ceramics or non-ferromagnetic steel of low electrical conductivity. 
     
     
       7. A pump according to claim 4, wherein the permanent magnet poles are surrounded by a band on their outer circumference. 
     
     
       8. A pump according to claim 7, wherein the band is comprised of fiber-reinforced plastics material or non-ferromagnetic steel of low electrical conductivity. 
     
     
       9. A pump according to claim 1, wherein the stator comprises stator parts, and the at least one stator carrier comprises two stator carriers attached to the housing on both sides thereof, respective stator parts being mounted in the two stator carriers. 
     
     
       10. A pump according to claim 1, wherein the housing has at least one radial flange, and the at least one stator carrier is threaded by means of axially directed screws to a respective radial flange. 
     
     
       11. A pump according to claim 1, wherein an outer diameter of the rotor is greater than or at the most equal to the length of the permanent magnet poles of one single rotor in an axial direction. 
     
     
       12. A pump according to claim 1, wherein the diameter of the impeller or of the housing on the pump side is approximately equal to the outside diameter of the stator carrier. 
     
     
       13. A pump according to claim 1, wherein the permanent magnet poles on the rotor are constituted by radially magnetized, highly coercive permanent magnets of the rare earths metal type, with a ferromagnetic return path disposed radially inside. 
     
     
       14. (Amended) A pump according to claim 1, wherein the permanent magnet poles on the rotor are constituted by circumferentially magnetized, highly coercive permanent magnets of the rare earths metal type and ferromagnetic flux wedges according to the flux collecting principle. 
     
     
       15. A pump according to claim 1, wherein the stator currents within the coil windings of the stator are electronically commutated. 
     
     
       16. A pump according to claim 1, wherein the power and the speed of the pump are infinitely variable within the operating range thereof. 
     
     
       17. An electric pump comprising: an impeller, a shaft and a motor having at least one permanent magnet rotor and a stator, wherein the impeller is coupled by the shaft to the at least one permanent magnet rotor of the electric motor;   a hermetically sealed housing in which the shaft is supported and which has openings for delivery side and suction side connections for material to be pumped;   wherein the rotor is disposed inside the housing and comprises a number of sector-shaped permanent magnet poles configured in the form of a disc and having an axial direction of magnetization;   wherein the stator of the electric motor is disposed outside the housing on a face side of the housing and has a number of coil windings disposed substantially in one plane, the number of coil windings corresponding substantially to the number of poles of the rotor; and   further comprising at least one stator carrier attached to the housing, the stator being mounted in the at least one stator carrier, the at least one stator carrier being of one-piece configuration so as to enclose the housing across an entire circumference thereof in a cup-shaped manner, the at least one stator carrier having a liquid for cooling the at least one stator.